The present invention refers to an arrangement for cardiopulmonary bypass according to the preamble of claim 1. The invention also refers to a method for cardiopulmonary bypass according to the preamble of claim 13.
Arrangements for cardiopulmonary bypass are frequently used in cardiothoracic surgery, especially in open heart surgery. A cardiotomy reservoir may be included in the arrangement for receiving blood entering the open operation wound, the open cardiotomy, during the surgery.
U.S. Pat. No. 6,770,048 discloses a combined device for cardiopulmonary bypass. The device comprises a venous blood reservoir and cardiotomy reservoir in an extracorporeal circuit, which may comprise a pump and an oxygenator.
Together with the blood from the operation wound, i.e. the open cardiotomy, gases, including carbon dioxide, may be sucked to the cardiotomy reservoir. If carbon dioxide is collected in the cardiotomy reservoir, the gas will be in contact with the blood. Since carbon dioxide dissolves easily in blood, there is a risk for increased levels of carbon dioxide in the blood.
It is also advantageous to add carbon dioxide to the operation wound, as is described in EP-1239915 and EP-1494606. The carbon dioxide will create a protective layer above the open cardiotomy. However, with such a supply of carbon dioxide, the problem of solution of carbon dioxide in the blood in the cardiotomy reservoir is further increased.
This problem may be at least partly remedied by increasing the flow of air or oxygen through the oxygenator, thereby increasing the amount of carbon dioxide being removed from the blood. The amount of carbon dioxide that can be removed by this measure is however limited.